In recent years, in the fields of automobiles, electronic products, industrial equipment and the like, there is an increasing trend of replacing a portion of a metal molded article with a resin molded article in order to respond to the demands of reducing carbon dioxide emission, manufacturing costs and the like. In connection with this, composite molded articles are widely used in which resin molded articles are integrated with metal molded articles. Without being limited to this, composite molded articles in which molded articles of similar or dissimilar materials are integrated together are also widely used.
As a method of manufacturing a composite molded article in which one molded article is integrated with another molded article, the following have been proposed, for example. Patent Document 1 proposes a method comprising: mixing a filler such as glass fiber with one resin to perform molding; subjecting the other resin to chemical, plasma, flame treatments and the like to remove a resin with a thickness of several tenths of micrometers to several tens of micrometers; and then while the other resin is allowed to make contact with a surface for adhering the other resin, filling and molding are performed, thereby achieving adhesion. Further, Patent Document 2 proposes a method comprising: irradiating a surface of one resin molded article with electromagnetic radiation to form a nano structure in the above surface; and then filling and molding are performed while the other resin molded article is allowed to make contact with the above surface, thereby achieving integration.
Further, Patent Document 3 proposes a method comprising: press-bonding a base material with a surface layer material, the base material having a shape of pits and protrusions in which hard fibers protrude from a surface thereof. Patent Document 4 proposes a method comprising: bonding molding materials together at their joining regions, the molding materials having metal fibers exposed on the surfaces thereof. Patent Document 5 proposes a method comprising: packing a filler metal into a joining region between a composite material and a layered composite materials such as an FRP material and FRM (fiber reinforced metal) or between a composite material and a butt weld joint, a lap weld joint, an edge weld joint or a fillet weld joint of a joint comprising a different metal material, the filler metal comprising a low percentage to 80% by weight of a reinforcement material, the reinforcement material comprising a reinforcement fiber, a tempered glass, a whisker in a thermoplastic resin, a thermosetting resin and a mixture of a thermoplastic resin and a thermosetting resin; and laser-welding the composite material and the layered composite material while performing the packing using a high-power continuous oscillation solid-state laser.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. H01-126339
Patent Document 2: Japanese Unexamined Patent Application, Publication No. 2011-529404
Patent Document 3: Japanese Unexamined Patent Application, Publication No. 2000-351189
Patent Document 4: Japanese Unexamined Patent Application, Publication No. H03-203291
Patent Document 5: Japanese Unexamined Patent Application, Publication No. 2010-247206